Video footage of the Russian air crash in which all 50 people on board were killed, including one Briton, shows the Tatarstan Airlines jet diving nose-first towards the ground before exploding in a huge ball of fire.

Investigators have determined that pilot error was almost certainly the cause of the disaster in the eastern regional capital Kazan.

After studying the plane’s black box data, investigators from the Inter-State Aviation Commission said the plane’s engines and other systems were functioning right up until it slammed into the ground.

According to its report, the two pilots had botched a landing attempt and were preparing to try again. They pulled up at a sharp angle, causing a loss of speed, then tried to gain it back by going into a steep dive at 2,200 feet.

The Commission confirmed what many had suspected in the immediate aftermath of the crash and added another woeful line to Russia’s abysmal air safety record. In 2011 it was deemed the most dangerous country in the world for air travel, according to aviation consultants Ascend.

Fatalities and crashes in Russia exceeded those in all other countries, the report found. That year, 10 fatal air accidents killed 119 people in Russia, including a crash in Yaroslavl that killed the entire Lokomotiv Yaroslavl professional hockey team.

Experts say pilot fatigue continues to plague of the country’s rapidly expanding airline industry, raising doubts that reforms have improved safety. Russia’s leadership has promised reforms to combat the rash of air accidents, but little has been achieved.

“It was not just one plane that crashed in Kazan but the entire airline industry and, to be honest, the entire Russian government system,” opposition State Duma deputy Dmitry Gudkov wrote on his blog after Sunday’s crash.

Officials have blamed small “dwarf” carriers for cutting corners and evading regulations, resulting in the majority of accidents. After the Yaroslavl crash in September 2011, then-president Dmitry Medvedev called for “the number of airlines to be radically reduced”, and the Transportation Ministry drafted legislation stipulating that a company have a minimum of 10 planes to operate, to be raised to 20 planes by this year.

No law was passed, however, and in April 2012 a flight packed with oil executives operated by the small carrier Utair crashed in the Siberian region of Tyumen, killing 31.

Tatarstan Airlines, the operator of the Boeing 737-500 that crashed Sunday, is a small carrier, with seven planes, according to its website. The plane was reportedly being leased from a Bulgarian company and was previously involved in minor accidents in Brazil and Kazan. Tatarstan Airlines could not be reached for comment.

According to the prosecutor general’s office, human error causes about 80 per cent of air crashes in Russia, state news agency RIA-Novosti reported. Flight personnel unions say packed flight schedules are increasing mistakes, and the rapid pace of growth in Russia’s air industry was forcing pilots to fly too much, with regulations not being properly enforced.

“The main problem is fatigue of pilots,” Igor Obodkov, spokesman for the Sheremetyevo Air Staff Union, a union for employees of Russia’s largest Aeroflot airline, told The Independent.

Russian law stipulates 70 days of vacation for pilots each year, but an investigation of Aeroflot found that many pilots were owed 100 back-days, Obodkov said.

The pilots’ “tiredness could have influenced events” that led to the Kazan disaster, he added.

He noted that the Commission’s report of the April 2012 crash in Tyumen showed that the plane’s pilots had not had enough rest between flights.

“We are suspecting that they will find same thing here. People were tired,” Obodkov said.